In his physics class, Omar took 4 tests. His scores were 87, 80, 95, and 78. What was his average score on the tests?
Solution: The average is the sum of his scores divided by the number of scores. There are 4 scores and their sum is $87 + 80 + 95 + 78 = 340$ His average score is $340 \div 4 = 85$.